FIGURE 1.

The biogenesis and cellular-uptake of extracellular vesicles. Microvesicles are released directly from the plasma membrane via outward budding. The biogenesis of exosomes follows the endocytic-exocytic pathway, inward budding from the plasma membrane to form early endosomes. Late endosomal membrane invagination results in the loading of cytosolic proteins/RNAs, which further forms the exosomal precursor–intraluminal vesicles (ILVs) in multivesicular bodies (MVBs). Exosomes are then secreted into the extracellular space after fusion with the plasma membrane via an ESCRT-dependent or ESCRT-independent pathway. Exosomes can be taken up by recipient cells through endocytosis, direct fusion, or binding to surface proteins, causing the transfer of oncogenic cargoes, and changing the biological behaviors of recipient cells. A multitude of non-coding RNA species (e.g., miRNAs, circRNAs, lncRNAs) are contained in exosome. The roles of exosomes in ovarian cancer are also shown. ESCRT, endosomal sorting complex required for transport; MHC, major histocompatibility complex; miRNA, microRNA; circRNA, circular RNA; lncRNA, long non-coding RNA.